1. Field of the Invention
The present invention relates to weapons of the type having a reciprocating block which recoils under the influence of an exploding shell in the chamber against a spring force holding it closed against the breech. As the breech block recoils, it picks up the spent shell casing and ejects it thus clearing the chamber to receive another shell. When the block moves forward again under the influence of a recoil spring, it picks up another shell and moves it into the chamber in position to be fired. Of particular interest are those weapons having reciprocating breech blocks that can accommodate the modern thin-jacketed shells containing a so-called "magnum" load which, when fired, generate sufficient pressure in the chamber to expand the casing and cause the weapon to jam.
2. Description of the Related Art
A .45 caliber pistol develops approximately 390 foot pounds of muzzle energy using a 185 grain bullet which will have a muzzle velocity of around 950 feet per second. This is a very popular weapon, however, it is expensive to shoot in that, at the present time at least, shells of good quality sell for somewhere between $25.00 and $30.00 for a box of fifty.
The Winchester Arms Company introduced a few years ago what is known as a .22 magnum cartridge which presently sells for only about $5.00 for a box of fifty yet, in many respects, it performs comparably to the traditional .45 caliber shell. Using only a 40 grain bullet, it develops 392 foot pounds of muzzle energy and has a 2000 foot per second muzzle velocity using a slow-burning rifle powder. Prospects are that the same cartridge filled with a fast-burning powder charge of equal size will develop muzzle energy of 2000 foot pounds and will have a muzzle velocity of 3200 to 3500 feet per second.
Unfortunately, there have been a lot of problems associated with this particular cartridge caused largely by the fact that it has a very thin-walled jacket and is quite long. What happens is that the casing cannot withstand the bore pressure and, if the block is not held securely in place against the breech for an interval that permits the pressure generated in the bore to decrease substantially, the head of the cartridge casing blows off leaving the rest of the empty jacket in the chamber since there is nothing left for the extractor to get a hold of to extract it. The next cartridge fed into the chamber either jams as it tries to enter the portion of the jacket left behind or, alternatively, the shell fires with the block only partially closed thus causing a serious and potentially very dangerous situation for the shooter. Neither of these options is acceptable and, therefore, there is a need for a solution to this problem of the head of the shell being blown off due to premature opening of the breech.
It can be shown that the pressure pulse associated with rapid burning of the powder contained within the shell casing builds almost instantaneously to a peak and then decays somewhat more slowly as the bullet leaves the muzzle and thereby creates an ever-increasing volume for the gases to expand into. There is, of course, some pressure at which the head of any cartridge will blow off if left unconfined in the chamber of the weapon. Fortunately, most cartridges are designed to withstand the pressure at which damage thereto would occur either by lessening the powder charge or increasing the strength of the shell casing or both. In some thin-jacketed shells filled with a proportionately greater powder charge like the one previously described, this is not the case and the casing can, in fact, rupture if not fully confined in the chamber until the pressure decays to a level at which it is safe to permit the block to back off and open the breech.
The so-called "recoil" of a weapon is that reactive force which causes it to move rearward as the result of the forward motion of the bullet as it exits the barrel and the pressure applied to the breech block by the rapidly-expanding gases trapped in the barrel between the bullet and its now-empty casing. Firearms, especially the handheld type, are equipped with various types of recoil-absorption mechanisms, some mechanical, others hydraulic and, in the case of certain high-powered cartridges, part of the recoil is customarily absorbed by bleeding off a portion of the muzzle pressure and conducting it to a position behind the block. Regardless of the type of recoil-absorption mechanism used, its primary function is that of a shock absorber. In automatic and semi-automatic weapons, on the other hand, the recoil-absorption mechanism is also used to perform the additional function of returning the block to its firing position covering the breech during which excursion it picks up an unfired shell and moves it into the chamber. Whatever the function or functions to be performed by the recoil-absorption mechanism in a firearm, of critical importance is always that of holding the block in place such that it holds the cartridge in the chamber for the interval required, no matter how brief, until the pressure inside the barrel has dissipated to a level at which it can be safely opened. This all-important function is adequately addressed by many recoil-absorption systems designed for use with ordinary ammunition; however, these same systems have proven to be inadequate and very dangerous when employed with thin-jacketed high-powered ammunition. Moreover, just solving the problem of holding the block closed until the muzzle pressure dissipates to a level where the breech can be safely opened is not the entire answer because its solution fails to address the remaining problem of how to best and most efficiently handle the recoil of the block without undue shock to the shooter or an overall loss in accuracy, especially in those rapid-fire firearms having one that reciprocates very quickly.
The prior art systems known to applicant for controlling the excessively high muzzle pressures generated by these modern thin-jacketed cartridges have all been based upon the principal of, first of all, not letting the muzzle pressure build up to the level at which it can damage the shell casing followed by delaying the opening of the breech in some fashion until the muzzle pressure is further reduced to a point at which the breech can be safely opened. Specifically, the muzzled pressure is limited to a level significantly below that which the powder charge would otherwise produce in a closed system by bleeding off a portion of the gas pressure ahead of the bullet as it moves toward the muzzle. While this pressure is confined, nevertheless, it expands into a volume outside the barrel thus lessening the pressure therein well below that which would exist if such an "escape" were not provided. The maximum muzzle pressure is, therefore, limited unless, of course, the by-pass system gets plugged up which, frankly, happens very quickly after only a relatively few rounds are fired.
The delay system that is used to hold the block in closed position momentarily until the muzzle pressure further dissipates to a level at which the breech can be safely opened oftentimes comprises a mechanical system of some sort that remains locked until the muzzle pressure bled off from the barrel is shunted around to open it and thus allow the block to retract. Such systems have little, if anything, to do with the absorption of the recoil, only the reduction of the excess muzzle pressure and putting it to use in delaying the opening of the breech. As a matter of fact, essentially the full impact of the recoil is transferred to the shooter through the block and mechanical system holding it closed since, for all practical purposes, nothing in the system yields and provides a shock absorbing function until most of the muzzle pressure has dissipated and its effect has already been felt. In these systems, once the block has been released, its rearward movement is usually slowed down by a conventional spring-biased recoil-absorption mechanism, however, at this point most of the damage has been done and there is very little left in the way of recoil to absorb.
The main difficulty with these systems is that they just do not work. As the powder ignites, all sorts of solid residues are generated which very quickly clog up the bleed-off system rendering it completely, or at least partially, inoperative. Moreover, as the bleed ports and passages become more and more plugged up, the muzzle pressure rises and the whole system fails to achieve that for which it was designed. These systems are most often found in rapid-fire automatic or semi-automatic weapons of the type used by the armed forces, law enforcement people and special security agencies, none of which can tolerate a weapon that cannot be relied upon. Also, the ineffectiveness of these weapons to handle the recoil properly is a major factor in their being highly inaccurate even at short range.
Other systems for handling recoil are purely mechanical and do not involve bleeding off a portion of the muzzle pressure. Some even incorporate block-opening delay mechanisms of one type or another which cooperate with the conventional spring-biased recoil absorption systems to momentarily delay the opening of the breech at which time they become wholly inoperative. As such, they have little or no effect in terms of recoil absorption for the simple reason that they permit nearly all of the reactive forces to pass directly through to the primary recoil absorption system and back to the shooter at the very time these forces are at near their maximum level. In other words, just about the time that the shooter needs the most recoil protection, the supplementary mechanical delay mechanism has ceased to function thus leaving the primary spring-biased conventional system to take care of the major portion of the recoil all by itself. Equally significant, however, is the inability of such systems to hold the block closed under the abnormally high pressures generated inside the barrel of a weapon firing the modern thin-jacketed magnum ammunition. While recoil absorption is important and a much sought-after characteristic in a firearm, especially automatic and semi-automatic ones in terms of accuracy, it is, nevertheless, subordinate to the absolute necessity for holding the breech block closed against the excessive internal pressures generated by the modern-day thin-jacketed ammunition. Insofar as applicant is aware, the only solution to this problem up to the present time involves reducing the peak pressure by bleeding off a portion of the gases generated inside the barrel and using these gases to assist the primary spring-biased recoil system in holding the breech closed until such time as it can be safely opened without blowing off the head of the shell casing.
A properly designed recoil system, whether used for high-powered thin-jacketed ammunition or conventional loads must, of necessity, take into account several other factors such as, for example, the mass and weight of the block versus the length of the weapon and the size of the spring required to bring it to a stop; the rapidity with which the block reciprocates which is also a function of its weight and the spring-bias acting to return it to closed position; the reactive forces which have to be absorbed in order to bring the block to a stop before it strikes some abutment, etc. All of these factors involve trade-offs to some greater or lesser degree but it all gets back, eventually, to initially containing the explosive forces without letting the breech open prematurely and thereafter cancelling out as best one can the reactive forces generated by the confined explosion in the barrel before they reach the shooter.
Accordingly, there is a pressing need for a gasless recoil system for use with firearms of the reciprocating breech block type that is effective for use with all types of ammunition but which is especially useful to contain those excessive forces generated in the barrel by the thin-jacketed ammunition without permitting the breech to open prematurely resulting in the weapon jamming or, worse, causing injury to the shooter. Of secondary importance, but nonetheless significant, is to design such a system which will, in addition, dampen out the reactive forces generated by the explosion inside the barrel thus improving the accuracy of the weapon and the comfort associated with firing it while, at the same time, keeping it light, compact and, in the case of rapid-fire weaponry, manageable in the sense of not firing too fast.
3. Objects of the Invention
It is, therefore, the principal object of the present invention to provide a novel and improved gasless recoil absorption system for firearms of the type employing reciprocating breech blocks.
A second objective of the invention herein disclosed and claimed is that of providing a system of the type aforementioned which is especially useful in those weapons firing thin-walled magnum cartridges.
Another object of the within-described invention is the provision of a recoil absorption system which includes both primary and secondary spring-biased subassemblies, both of which are initially operative to slow down as well as resist the reactive forces acting upon the breech block as it moves away from the breech until these forces are overcome to a degree where those which remain can be handled by the primary system alone whereupon the secondary subassembly becomes essentially inoperative.
Still another object is to provide a purely mechanical recoil absorption system which, due to its unique division of the task of overcoming the reactive forces acting upon the breech block in two or more stages, results in a much more compact yet essentially recoilless weapon having greatly increased accuracy particularly in the rapid-fire automatic and semi-automatic modes.
Yet another object is to provide an automatic weapon which is easier to handle and far more accurate than other rapid-fire weapons of the same caliber, yet, has the fire power of much larger caliber so-called "Class 3" firearms which are more commonly described as "machine guns".
A further objective is that of providing a more compact spring recoil absorption mechanism involving two or more stages of bias cooperating with one another to effectively slow down and eventually stop and reverse even a heavy breech block in a very short distance without, at the same time, shortening the recoil cycle in an automatic weapon to the degree where the rate-of-fire becomes excessive and perhaps faster than that at which the spent shell casing can be ejected and a new round picked up and inserted into the chamber without jamming.
Other objects of the invention forming the subject matter hereof include those of providing a handheld repeating weapon which is readily adapted for use with ammunition of different calibers, loads and shell casings; can be fired a round at a time, semi-automatically or automatically; and a weapon of the type aforementioned which is safe, rugged, compact, versatile, reliable, easy to use and even decorative.